In the last decade, budget support (BS) has become one of the most popular and controversial aid modalities. The tensions between the EU and member states regarding the use of this modality set in motion interesting policy influencing dynamics. We reconstruct these processes looking at two turning-points (the inception and the subsequent reform of the BS policy) and compare over time the positions, capacities and policies of three EU member states with varying positions towards BS: Germany, the UK and Belgium. We find no evidence that the EU has been able to download its BS policies. Instead we find some evidence of limited delegation to the EU level, and strong indications of member states uploading policy preferences to the EU level. We further argue that domestic politics in member states matters more than EU aid policy prescriptions, and that the EU's policy space is crucially influenced by its own and member states capacities and autonomy to build political alliances around policy preferences.